CN102394751B - One-time pad password system based on visual cryptography - Google Patents

Abstract

The invention provides a one-time pad password system based on visual cryptography. The technical scheme is that the one-time pad password system comprises a main-control module, an identity characteristic input interface, a visual information display terminal, a password input terminal and a plurality of subscriber masking pictures, wherein each subscriber masking picture corresponds to a subscriber; the identity characteristic input interface receives the identity characteristic data input of subscribers and sends the identity characteristic data input to the main-control module; the password input terminal receives the password input and sends the password input to the main-control module; the visual information display terminal receives visual cryptography subsidiary pictures sent by the main-control module and displays the visual cryptography subsidiary pictures to the subscribers; the subscribers place the possessed subscriber masking pictures on a first aligning frame to acquire the password P at the time; the main-control module comprises a master control program and a database; the main-control module takes a computer system as the platform and further comprises another master control program and another database to achieve subscriber register and authentication identification. The one-time pad password system provided by the invention can achieve safe, convenient andefficient subscriber identity authentication.

Description

One-time pad password system based on visual cryptography

Technical field

The invention belongs to information security field, more concretely, the present invention relates to a kind of password system with one-time pad characteristics that utilizes visual cryptography to realize.

Background technology

One width of cloth original image is resolved into the random subgraph of two width of cloth, because the randomness of decomposing, when utilizing people's vision to observe two width of cloth subgraphs, can't obtain any information of original image, it is impossible namely wanting to obtain original image information from single subgraph.Only have when two width of cloth subgraphs fully when superimposed, from the angle of visual effect, original image is just rebuilt.The technology of utilizing above-mentioned principle to be encrypted deciphering is visual cryptography, claims that usually two width of cloth subgraphs are the visual cryptography subgraph.Visual cryptography can be applied in information security field, carries out the authentication of validated user.

The method of using password to carry out authentication comprises static password mode and dynamic password mode.The static password mode is confirmed user's legitimacy by user name and the coupling of relative fixedly password.This authentication mode is because of the nature static of password and reuse, and has safety defects such as easily leaking, easily steal, easily guess, easily crack.The dynamic password mode comprises one-time pad password form, namely is to replace static password with one-time password, when each authentication, and random the generation when time password.This mode overcomes the various safety defects of traditional static password, so that the fail safe of verification process is greatly improved.

Realize one-time pad password form, maximum difficulty is that the password that generates during how with each authentication passes to validated user and learns, simultaneously in transmittance process, avoid losing, revealing, avoid loaded down with trivial details operation, for a long time wait, high a series of practical problems such as cost.

As previously mentioned, use visual cryptography can realize the one-time pad password.When each authentication, this password information is added in the original image of generation, namely utilize vision to observe and can from original image, obtain this password.The decrypted image that the user is held is as first visual cryptography subgraph, utilizes first visual cryptography subgraph and this to generate original image and obtains second visual cryptography subgraph, and show by display device.When the user operated, second visual cryptography subgraph on the decrypted image that oneself is held (i.e. first visual cryptography subgraph) and the display device stacked and reconstructs original image, read when time password of authentication.In the system that reality is used, can allow the user input again the password of this authentication, if password is correct, can finish this authentication.At present, the relevant data of utilizing visual cryptography to realize the one-time pad password system not yet retrieves.

Summary of the invention

The purpose of this invention is to provide a kind of one-time pad password system based on visual cryptography, finish safety, convenient, effective authenticating user identification.

Technical scheme of the present invention is: a kind of one-time pad password system based on visual cryptography comprises main control module, identity characteristic input interface, visual information display terminal, password input terminal, several user's mask artworks.Every corresponding user of user's mask artwork.

The identity characteristic input interface receives user's identity characteristic data input, sends to main control module.The password input terminal receives the password input, and sends to main control module.

The visual information display terminal receives the visual cryptography subgraph that main control module sends, and is shown to the user.User's mask artwork that the user will have is put on the first alignment frame, can obtain as time password P.

Main control module comprises primary control program and database.Main control module also comprises primary control program and database take computer system as platform, under the control of primary control program, and completing user registration and authentication identifying.Database is used for storage user's mask artwork and subscriber identity information.

When main control module is carried out user registration course: receive the identity characteristic data that the identity characteristic input interface sends, produce at random a width of cloth user mask artwork, deposit this user's mask artwork and user's identity characteristic data in database as this user's information together.Wherein, the process that produces a width of cloth user mask artwork is:

If six basic picture element matrixs are $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),$ 0 pixel that represents black gray wherein, 1 represents the pixel of white gray;

As a foundation drawing point, then six basic picture element matrixs form six different foundation drawing points with each basic picture element matrix, and each foundation drawing point comprises 2 * 2 pixels.Choose at random any foundation drawing point and arrange, the image of generation is user's mask artwork.Each user allots user's mask artwork.

When main control module is carried out the authentication identifying, may further comprise the steps:

The first step: search user's mask artwork

The identity characteristic input interface receives the user identity feature, and the identity characteristic data of storing in this identity characteristic and the database are mated, and finds user's mask artwork W1 corresponding to this user identity feature.

Second step: generate associated picture

(1) step: generate original image

Random n (n is any positive integer) the position password that generates is designated as P.

If two original pixels matrixes are $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$ As an original graph point, then two original pixels matrixes form two different original graph points with each original pixels matrix, and each original graph point comprises 2 * 2 pixels.Wherein $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right)$ Represent the original graph point of white, $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right)$ Represent the original graph point of black.

Generate original image, original image is the 0-1 gray level image.Utilize vision to observe and to obtain password P from original image.

If comprising the zone of password P in the original image is effective range, effective range to be expanded, the expansion rule is: if the pixel in the effective range is the white pixel point, then expand the original graph point that becomes white, namely $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right);$ If the pixel in the effective range is black pixel point, then expand the original graph point that becomes black, namely $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$ Effective range is expanded the rear image that forms be designated as effective image S.

(2) step: generate the visual cryptography subgraph

At first user's mask artwork W1 and effective image S are alignd.The concept of definition alignment unit is: an alignment unit refers to any one foundation drawing point in user's mask artwork W1, and an alignment unit refers to any one original graph point in effective image S.The rule of alignment is: when user's mask artwork W1 and effective image S were stacked, all alignment unit of effective image S all covered in the alignment unit of user's mask artwork W1.If after user's mask artwork W1 and the effective image S alignment, the closed curve that the borderline pixel of user's mask artwork W1 forms is the first alignment frame, is generally rectangle; The closed curve that the borderline pixel of effective image S forms is the second alignment frame, is generally rectangle, records the size of relative position W He each frame of two frames.By relative position W as can be known, the original graph point of the capable j row of effective image S i covers on the foundation drawing point of user's mask artwork W1 the i ' row j ' row, and is namely corresponding.

If expand picture element matrix and be for five $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right),$ Each is expanded picture element matrix as an exploded view point, then expand five exploded view points of picture element matrix formation for five, each exploded view point comprises 2 * 2 pixels.

If ten resolve a picture dot matrixes are $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right).$ As an exploded view point, then ten resolve a picture dot matrixes form ten exploded view points with each resolve a picture dot matrix, and each exploded view point comprises 2 * 2 pixels.

Utilize effective image S to generate the exploded view picture, the exploded view picture is made of the exploded view point, the create-rule of each exploded view point is: the original graph of the capable j row of effective image S i is put corresponding exploded view as the exploded view point of the capable j row of i, if the original graph point of the capable j row of effective image S i is the original graph point of white, then three pixels are black in the exploded view point of the capable j row of i, a pixel is white, and the position of white pixel point is in two white pixel point positions in foundation drawing point corresponding to user's mask artwork W1 the i ' row j ' row any one, chooses at random the white original graph point of qualified exploded view point replacement; Otherwise the original graph point of black is replaced to the exploded view point $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$

Recycling exploded view picture and user's mask artwork W1 generate visual cryptography subgraph W2.Visual cryptography subgraph W2 is made of the exploded view point, with the exploded view point in the exploded view point replacement exploded view picture, the replacement condition satisfies: when the value of the value of corresponding pixel points and the exploded view point corresponding pixel points of the capable j row of visual cryptography subgraph W2 i multiplied each other in the alignment unit (foundation drawing point) of user's mask artwork W1 the i ' row j ' row, the result who obtains was the value of the corresponding pixel points of the exploded view point that is listed as of the capable j of exploded view picture correspondence i.

The 3rd step: check password

The first alignment frame is presented at VDT, presses relative position W and in the second alignment frame, show the visual cryptography subgraph.

The user who receives the transmission of password input terminal enters password.If the password of input is P, judge that then the user is validated user, the output legal information is to application system.Otherwise the output information unauthorized is to application system.

As a further improvement on the present invention, the highest in order to realize fail safe, can make simultaneously the utilance of user's mask artwork maximum, the length of original image is half of length of user's mask artwork, the width of original image is half of width of user's mask artwork.

Beneficial effect of the present invention is:

1. realization dynamic password.When the user carried out authentication at every turn, password P and original image all were random the generations, have uncertainty, therefore can realize the one-time pad dynamic password.

2. manner of decryption is simple.The present invention is when identifying user identity, and only utilizing vision is that naked eyes just can be decrypted acquisition password P.

3. safe.Utilize the visual cryptography subgraph of visual information display terminal output output, do not comprise any password information of original image output, the disabled user can't obtain password, and therefore output, use procedure are safe and reliable.

4. system provided by the invention utilizes prior art equipment to realize easily, have cost low, use simple characteristics.

Description of drawings

Fig. 1 is system provided by the invention theory of constitution schematic diagram;

Fig. 2 is the Principle of Process schematic diagram that comprises among the present invention;

Fig. 3 is user's mask artwork W1 that the present invention is used for the principle explanation;

Fig. 4 is the original image that the present invention is used for the principle explanation;

Fig. 5 is the effective image S that the present invention is used for the principle explanation

Fig. 6 is the exploded view picture that the present invention is used for the principle explanation;

Fig. 7 is the visual cryptography subgraph W2 that the present invention is used for the principle explanation;

Fig. 8 is user's mask artwork W1 that emulation experiment one of the present invention generates;

Fig. 9 is the visual cryptography subgraph W2 that emulation experiment one of the present invention generates;

Figure 10 is the exploded view picture that emulation experiment one of the present invention generates.

Embodiment

The present invention is described in detail below in conjunction with example.

Fig. 1 is system of the present invention theory of constitution schematic diagram, Fig. 2 is operating process schematic diagram of the present invention, Fig. 3 to Fig. 7 be utilize the specific embodiment of the present invention carry out for principle explanation the result, Fig. 8 to Figure 10 utilizes the specific embodiment of the present invention to carry out the result of emulation experiment one.

As shown in Figure 1, the one-time pad password system based on visual cryptography provided by the invention comprises main control module, identity characteristic input interface, visual information display terminal, password input terminal, several user's mask artworks.Main control module utilizes the equipment platforms such as computer or embedded system, single-chip microcomputer to realize.Main control module comprises primary control program and database, utilizes software to realize the function of primary control program, comprises that the user registers and authenticate identification.Database storage user's mask artwork data and identity characteristic data.The identity characteristic input interface is certain collecting device or certain Message Entry Device, gathers the user identity characteristic and sends to main control module; Therefore the user identity characteristic can be the information such as fingerprint, iris, vein, name, code.The visual information display terminal is image display, can be liquid crystal display screen, CRT monitor etc., and output visual cryptography subgraph is shown to the user.The password input terminal is the input equipments such as keyboard or touch-screen, receives the password of user's input, and sends to main control module.Each user allots user's mask artwork, and user's mask artwork is the piece image that is generated by main control module, and every user's mask artwork is not identical.

In user's use procedure, comprise that the user registers and authenticate two processes of identification.User registration course is shown in Fig. 2 (a), the user is at first by identity characteristic input interface input user identity characteristic, then by the identity characteristic interface identity characteristic data are sent to main control module, after main control module receives the identity characteristic data, generate and output user mask artwork.User's mask artwork of main control module output is printed on the translucent film, is preserved by the user.The authentication identifying is shown in Fig. 2 (b), the user is by identity characteristic input interface input identity characteristic data, main control module receive after these identity characteristic data with database in the identity characteristic data of storing mate, if the match is successful, find user's mask artwork W1 corresponding to this user identity feature; Then generate associated picture, comprise and generate original image and generate visual cryptography subgraph W2, wherein when generating the visual cryptography subgraph, generate the first alignment frame and the second alignment frame, record the size of two frame relative position W and each frame, from original image, can find out password P; The size of the visual cryptography subgraph W2 that generates and two frame relative position W and each frame sent be given to VDT, VDT shows the first alignment frame, press relative position W demonstration visual cryptography subgraph W2 in the second alignment frame; After the user sees visual cryptography subgraph W2, oneself user's mask artwork W1 is placed into the frame coincidence so that align with first in user's mask artwork border on the first alignment frame, can sees password P; The user is by the password input terminal P that enters password, and main control module is checked password and judged whether the user is validated user, and the output corresponding information is to application system.

Wherein, when generating user's mask artwork W1, choose at random the foundation drawing point and arrange, the image of generation is user's mask artwork.Be illustrated in figure 3 as for the principle explanation, utilize user's mask artwork W1 of 7 * 5=35 foundation drawing dot generation.

Wherein, when generating at random any n position password P, password can be numeral, upper and lower case letter or some additional characters.When carrying out illustrating for principle, generate at random n=1 position password, the random password that generates be digital " 8 ", i.e. P=8.

Wherein, when generating original image, call the corresponding template of numeral, letter or additional character in the password of generation (template is the image that numeral, letter or additional character that black picture element consists of are arranged), begin to take shape the framework of original image, then at the random filling in other zones monochrome pixels point, generate the image of a 0-1 gray scale, finally consist of original image, and want the utility vision can find out password P from original image.Be illustrated in figure 4 as the original image for the principle explanation, therefrom can clearly tell password P=8.When practical application, original image size to choose best resolution with existing display device identical, such as 640 * 480,1024 * 768 etc., the convenient so follow-up operation such as stack.If comprising the zone of password P in the original image is effective range, effective range to be expanded, the expansion rule is: if the pixel in the effective range is the white pixel point, then expand the original graph point that becomes white, namely $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right);$ If the pixel in the effective range is black pixel point, then expand the original graph point that becomes black, namely $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$ Effective range is expanded the rear image that forms be designated as effective image S, as shown in Figure 5.

Wherein, when generating visual cryptography subgraph W2, at first be with user's mask artwork W1 and effective image S alignment.The concept of definition alignment unit is: an alignment unit refers to any one foundation drawing point in user's mask artwork W1, and an alignment unit refers to any one original graph point in effective image S.The rule of alignment is: when user's mask artwork W1 and effective image S were stacked, all alignment unit of effective image S all covered in the alignment unit of user's mask artwork W1.If after user's mask artwork W1 and the effective image S alignment, the closed curve that the borderline pixel of user's mask artwork W1 forms is the first alignment frame, is generally rectangle; The closed curve that the borderline pixel of effective image S forms is the second alignment frame, is generally rectangle, records the size of relative position W He each frame of two frames.By relative position W as can be known, the original graph point of the capable j row of effective image S i covers on the foundation drawing point of user's mask artwork W1 the i ' row j ' row, and is namely corresponding.In the experiment that is used for the principle explanation, the first alignment frame the measure-alike of frame that align with second all is 14 * 10, and i=1, j=1, i '=1, j '=1.

If expand picture element matrix and be for five $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right),$ Each is expanded picture element matrix as an exploded view point, then expand five exploded view points of picture element matrix formation for five, each exploded view point comprises 2 * 2 pixels.

If ten resolve a picture dot matrixes are $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right).$ As an exploded view point, then ten resolve a picture dot matrixes form ten exploded view points with each resolve a picture dot matrix, and each exploded view point comprises 2 * 2 pixels.

Utilize effective image S to generate the exploded view picture, the exploded view picture is made of the exploded view point, the create-rule of each exploded view point is: the original graph of the capable j row of effective image S i is put corresponding exploded view as the exploded view point of the capable j row of i, if the original graph point of the capable j row of effective image S i is the original graph point of white, then three pixels are black in the exploded view point of the capable j row of i, a pixel is white, and the position of white pixel point is in two white pixel point positions of corresponding foundation drawing point in foundation drawing point corresponding to user's mask artwork W1 the i ' row j ' row any one, chooses at random the white original graph point of qualified exploded view point replacement; Otherwise the original graph point of black is replaced to the exploded view point $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$ Shown in Figure 6 is the exploded view picture that generates for the principle explanation.Be used for the effective image S of principle explanation at Fig. 5, effective image S the 1st row the 1st row original graph point is $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right),$ Be the original graph point of black, then Fig. 6 is black for four pixels of the exploded view point of exploded view picture the 1st row the 1st row of principle explanation, is $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right);$ Be used for the effective image S of principle explanation at Fig. 5, the 1st row the 2nd row original graph point is $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right),$ The foundation drawing point of namely white, and corresponding with effective image S user's mask artwork W1 the 1st row the 2nd row is $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ Then the exploded view point of the 1st row the 2nd row can for $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right)$ Or $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ The exploded view point that Fig. 6 chooses at random for the exploded view picture of principle explanation is $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right).$

Recycling exploded view picture and user's mask artwork W1 generate visual cryptography subgraph W2.Visual cryptography subgraph W2 is made of the exploded view point, with the exploded view point in the exploded view point replacement exploded view picture, the replacement condition satisfies: when the value of the value of corresponding pixel points and the exploded view point corresponding pixel points of the capable j row of visual cryptography subgraph W2 i multiplied each other in the alignment unit (foundation drawing point) of user's mask artwork W1 the i ' row j ' row, the result who obtains was the value of the corresponding pixel points of the exploded view point that is listed as of the capable j of exploded view picture correspondence i.Fig. 7 is the visual cryptography subgraph W2 for the principle explanation, puts corresponding exploded view such as the exploded view of visual cryptography subgraph W2 the 1st row the 1st row as the exploded view point that the 1st row the 1st is listed as to be $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right),$ The alignment unit (foundation drawing point) of the 1st row the 1st row is among the respective user mask artwork W1 $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ The exploded view point that then satisfies the replacement condition is the exploded view point that is listed as with visual cryptography subgraph W2 the 1st row the 1st $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right)$ When respective pixel multiplies each other, namely $\left(\begin{array}{cc}0\×1& 0\×0\\ 1\×0& 1\×0\end{array}\right)$ The result who obtains is that exploded view is as the exploded view point of the 1st row the 1st row $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right).$ Because in the experiment that is used for the principle explanation, the size of the first alignment frame, the second alignment frame, user's mask artwork W1, visual cryptography subgraph W2 is all identical, therefore the border of the first alignment frame, the second alignment frame, visual cryptography subgraph W2 all overlaps, covered the first alignment frame when in the second alignment frame, showing the visual cryptography subgraph.

Wherein, when checking password, the first alignment frame is presented at VDT, presses relative position W and in the second alignment frame, show the visual cryptography subgraph.The user who receives the transmission of password input terminal enters password.If the password of input is P, judge that then the user is validated user, the output legal information is to application system.Otherwise the output information unauthorized is to application system.Be used for principle illustrative experiment, password P=8.

Fig. 8 is user's mask artwork W1 of emulation experiment one, is of a size of 160 * 120.Fig. 9 is the visual cryptography subgraph W2 of emulation experiment one, is of a size of 160 * 120.The first alignment frame the measure-alike of frame that align with second all is 160 * 120, and i=1, j=1, i '=1, j '=1.The size of the first alignment frame, the second alignment frame, user's mask artwork W1, visual cryptography subgraph W2 is all identical, therefore the border of the first alignment frame, the second alignment frame, visual cryptography subgraph W2 all overlaps, covered the first alignment frame when in the second alignment frame, showing the visual cryptography subgraph.Figure 10 is the effect of the exploded view picture that obtains after user's mask artwork W1 in the emulation experiment one and visual cryptography subgraph W2 stack, as can be seen from the figure password P=199301.

Claims (2)

1. the one-time pad password system based on visual cryptography is characterized in that, comprises main control module, identity characteristic input interface, visual information display terminal, password input terminal, several user's mask artworks; Every corresponding user of user's mask artwork;

The identity characteristic input interface receives user's identity characteristic data input, sends to main control module; The password input terminal receives the password input, and sends to main control module;

The visual information display terminal receives the visual cryptography subgraph that main control module sends, and is shown to the user; User's mask artwork that the user will have is put on the first alignment frame, can obtain as time password P;

Main control module also comprises primary control program and database take computer system as platform, under the control of primary control program, and completing user registration and authentication identifying; Database storage user's mask artwork data and identity characteristic data;

When main control module is carried out user registration course: receive the identity characteristic data that the identity characteristic input interface sends, produce at random a width of cloth user mask artwork, deposit this user's mask artwork and user's identity characteristic data in database as this user's information together; Wherein, the process that produces a width of cloth user mask artwork is:

If six basic picture element matrixs are $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),$ 0 pixel that represents black gray wherein, 1 represents the pixel of white gray;

As a foundation drawing point, then six basic picture element matrixs form six different foundation drawing points with each basic picture element matrix, and each foundation drawing point comprises 2 * 2 pixels; Choose at random any foundation drawing point and arrange, the image of generation is user's mask artwork; Each user allots user's mask artwork;

When main control module is carried out the authentication identifying, may further comprise the steps:

The first step: search user's mask artwork;

The identity characteristic input interface receives the user identity characteristic, and the identity characteristic data of storing in these identity characteristic data and the database are mated, and finds user's mask artwork W1 corresponding to this user identity feature;

Second step: generate associated picture;

(1) step: generate original image;

The random n position password that generates is designated as P, and wherein n is any positive integer;

If two original pixels matrixes are $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right);$ As an original graph point, then two original pixels matrixes form two different original graph points with each original pixels matrix, and each original graph point comprises 2 * 2 pixels; Wherein $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right)$ Represent the original graph point of white, $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right)$ Represent the original graph point of black;

Generate original image, original image is the 0-1 gray level image; Utilize vision to observe and to obtain password P from original image;

If comprising the zone of password P in the original image is effective range, effective range to be expanded, the expansion rule is: if the pixel in the effective range is the white pixel point, then expand the original graph point that becomes white, namely $\left(\begin{array}{cc}1& 1\\ 1& 1\end{array}\right);$ If the pixel in the effective range is black pixel point, then expand the original graph point that becomes black, namely $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right);$ Effective range is expanded the rear image that forms be designated as effective image S;

(2) step: generate the visual cryptography subgraph;

At first user's mask artwork W1 and effective image S are alignd; The concept of definition alignment unit is: an alignment unit refers to any one foundation drawing point in user's mask artwork W1, and an alignment unit refers to any one original graph point in effective image S; The rule of alignment is: when user's mask artwork W1 and effective image S were stacked, all alignment unit of effective image S all covered in the alignment unit of user's mask artwork W1; If after user's mask artwork W1 and the effective image S alignment, the closed curve that the borderline pixel of user's mask artwork W1 forms is the first alignment frame; The closed curve that the borderline pixel of effective image S forms is the second alignment frame, records the size of relative position W and each alignment frame of two alignment frames; By relative position W as can be known, the original graph point of the capable j row of effective image S i covers on the foundation drawing point of user's mask artwork W1 the i ' row j ' row, and is namely corresponding;

If expand picture element matrix and be for five $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right),$ Each is expanded picture element matrix as an exploded view point, then expand five exploded view points of picture element matrix formation for five, each exploded view point comprises 2 * 2 pixels;

If ten resolve a picture dot matrixes are $\left(\begin{array}{cc}0& 0\\ 1& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 0& 1\end{array}\right),$ $\left(\begin{array}{cc}0& 0\\ 1& 0\end{array}\right),$ $\left(\begin{array}{cc}0& 1\\ 0& 0\end{array}\right),$ $\left(\begin{array}{cc}1& 0\\ 0& 0\end{array}\right);$ As an exploded view point, then ten resolve a picture dot matrixes form ten exploded view points with each resolve a picture dot matrix, and each exploded view point comprises 2 * 2 pixels;

Utilize effective image S to generate the exploded view picture, the exploded view picture is made of the exploded view point, the create-rule of each exploded view point is: the original graph of the capable j row of effective image S i is put corresponding exploded view as the exploded view point of the capable j row of i, if the original graph point of the capable j row of effective image S i is the original graph point of white, then three pixels are black in the exploded view point of the capable j row of i, a pixel is white, and the position of white pixel point is in two white pixel point positions in foundation drawing point corresponding to user's mask artwork W1 the i ' row j ' row any one, chooses at random the white original graph point of qualified exploded view point replacement; Otherwise the original graph point of black is replaced to the exploded view point $\left(\begin{array}{cc}0& 0\\ 0& 0\end{array}\right);$

Recycling exploded view picture and user's mask artwork W1 generate visual cryptography subgraph W2; Visual cryptography subgraph W2 is made of the exploded view point, with the exploded view point in the exploded view point replacement exploded view picture, the replacement condition satisfies: when the value of the exploded view point corresponding pixel points that the capable j of the value of the foundation drawing point corresponding pixel points of user's mask artwork W1 the i ' row j ' row and visual cryptography subgraph W2 i is listed as multiplied each other, the result who obtains was the value of the corresponding pixel points of the exploded view point that is listed as of the capable j of exploded view picture correspondence i;

The 3rd step: check password;

The first alignment frame is presented at VDT, presses relative position W and in the second alignment frame, show the visual cryptography subgraph;

The user who receives the transmission of password input terminal enters password; If the password of input is P, judge that then the user is validated user, the output legal information is to application system; Otherwise the output information unauthorized is to application system.

2. the one-time pad password system based on visual cryptography according to claim 1 is characterized in that, the length of original image is half of length of user's mask artwork, and the width of original image is half of width of user's mask artwork.

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